A more thorough explanation:

Term: AACN

Definition: AACN stands for ANNO ANTE CHRISTUM NATUM, which is a Latin phrase meaning "years before the birth of Christ."

Example: The year 500 BCE is equivalent to 500 AACN.

Explanation: The term AACN is used to indicate the number of years before the birth of Jesus Christ. It is commonly used in historical and archaeological contexts to refer to events that occurred before the start of the Christian era. For example, the year 500 BCE is equivalent to 500 AACN, as it is 500 years before the birth of Christ.